Rapid assessments of recreational water quality

1. Rapid assessments of recreational water quality River Rally May 4, 2008 Donna Francy, Amie Brady, and Rebecca Bushon USGS Ohio Water Science Center

4. Today’s Agenda • Introduction to public health microbiology and bacterial indicators • Recreational water quality monitoring and assessment • Rapid analytical methods • Predictive models

5. Waterborne disease is a public health concern • Pathogens ingested from • drinking water • recreational water • contaminated fish or shellfish • Potential sources of pathogens • treated and untreated sewage • septic tanks • combined sewer overflows • landfills • animal waste

6. Incidence of recreational waterborne disease outbreaks in the US 2003-04, 62 waterborne disease outbreaks Etiologic Agents Identified: Bacteria 32.3% Protozoa 24.2% Virus 9.7% Chemical or Toxin 4.8% Centers for Disease Control and Prevention (CDCP)

7. Factors effecting incidence of waterborne Illness in the US • Increasingly greater threat to public health • Increase in population • Aging water-treatment systems • Aging population • Inadequately managed animal wastes • Lack of integrated regulatory approach

8. Types of waterborne pathogens Protozoa (larger, complex cells) Viruses (tiny, non-living) Bacteria (medium size, simple cells)

9. Pathogens and swimming-associated illnesses

10. Why don’t we test directly for waterborne pathogens? • Safety • May require direct manipulation of pathogenic organisms • Time and cost • Each pathogen must be detected using a different test • Requires processing of large volumes of sample • Pathogens usually are present in low concentrations

11. Indicators of fecal contamination • Indicator organisms • usually NOT pathogenic • "indicate" the possible presence of pathogenic organisms • Used to directly detect the presence of fecal contamination from warm-blooded animals E. coli

12. An Ideal Indicator Organism • Has an easy testing procedure • Is of human or animal fecal origin • Survives as long as, or longer, than pathogens • Present at densities related to the degree of fecal contamination • Is a "surrogate" for many different pathogens • Useful in fresh and saline waters Enterococci

13. Indicator Organisms—Problems • Present when there is no fecal contamination • Total coliforms and C. perfringens are found in soil so they are not exclusively indicators of fecal contamination • Absent when pathogens are present • E. coli may die off faster than viral pathogens • Density may not always relate well to the density of pathogens • E. coli can reproduce in warm, tropical waters

14. Methods for detecting indicators Membrane filtration method

15. Methods for detecting indicators Enzyme substrate tests

16. Membrane filtration method Modified mTEC agar E. coli colonies are magenta colored after incubation. Tests for Escherichia coli

17. Tests for Escherichia coli Enzyme substrate test Colilert E. coli positive wells fluoresce under UV light. (Total coliforms positive wells are yellow under ambient light.)

18. Membrane filtration method mEI agar Enterococci colonies have a blue halo. Tests for Enterococci

19. Tests for Enterococci Enzyme substrate test Enterolert Enterococci positive wells fluoresce blue under UV light.

20. Recreational water quality monitoring and assessment

21. Definitions • Criteria • Are not rules and do not have regulatory impact. • Scientific data and guidance on the potential human health risk involved in the water’s use (or in acceptable limits for aquatic life).

22. Definitions • Standards • Have regulatory impact • Rules set forth by the state or USEPA to protect users of waters (based on water-quality criteria) • For indicator bacteria, based on a quantifiable relation between • density of the indicator in water • the potential human health risk by the water’s use

23. Criteria for recreational waters Relation between E. coli and swimming-associated gastrointestinal illness

24. Criteria for recreational waters Relation between fecal coliformsand swimming-associated gastrointestinal illness

25. USEPA criteria for recreational waters—1986

26. USEPA BEACH PROGRAM • Beaches Environmental Assessment and Coastal Health Act of 2000 (BEACH) • Required the states to adopt criteria into standards • Required USEPA to develop new criteria by late 2005 • Required USEPA to address research topics such as modeling/monitoring, exposure and health effects • Provided grants to the states and local governments to develop new monitoring programs • Provided national beach guidance http://www.epa.gov/beaches

27. Need for rapid assessments At Ohio beaches, advisories are issued if E. coli is > 235 Culture results take 18-24 hours Water quality may change during that time

28. Solutions for rapid assessments • Rapid analytical methods • Description of qPCR and IMS/ATP • Rapid method studies • Predictive models • State of the science • Nowcasting at Ohio beaches and a recreational river

29. SURFACE RECOGNITION (IMS/ATP) SOLUTIONS? RAPID ANALYTICAL METHODS MOLECULAR (qPCR)

30. Unknowns qPCR RAPID METHOD • Target and amplify specific DNA sequences • Standard curve is created from analyzing known quantities of target organism • Unknown sample values are interpolated from the standard curve

31. Field Testing of qPCR Method • USGS and Northeast Ohio Regional Sewer District • Samples were collected from July – September 2006 and 2007 at two Lake Erie beaches - Edgewater and Villa Angela • Objective: Compare results obtained by qPCR to those of the conventional membrane-filtration method Project funded by the Ohio Department of Health

32. E. coli Standard Curve y = -3.5551x + 44.835 R2 = 0.9497

33. Correlations between qPCR and membrane filtration for E. coli r = 0.825 r = 0.786

34. qPCR results – Villa Angela 2007

35. Next Steps for qPCR • DNA extraction • Test different extraction kits • Analyze samples daily or weekly – not in batch format • qPCR • Find alternate source for assay reagents • Determine the best data interpretation procedure • Transfer technology to local agencies

36. M A G N E T IMS/ATP RAPID METHOD • Immunomagnetic separation (IMS) • Uses antibody-coated magnetic beads which bind to antigens present on the surface of cells • Adenosine triphosphate (ATP) • Energy molecule in all cells • Reported in Relative Light Units (RLU)

37. Field Testing and Technology Transfer of IMS/ATP Method • Water samples from Ohio Lake Erie beaches In cooperation with local and state cooperators (2005-2007) • Water samples from a recreational river (CVNP) In cooperation with federal cooperators (2004-2006) • Sewage samples from Ohio, NC, and CA plants and water samples from Avalon Beach, CA • In cooperation with Southern California Coastal Water Research Project (SCCRWP)

38. Correlations between IMS/ATP and membrane filtration for E. coli Cuyahoga River at Jaite, 2006 r=0.55 r=0.67 r=0.89

40. Villa Angela 2007: Relations to E. coli

41. Next steps for IMS/ATP method • Continue refinement of IMS/ATP • Identify additional antibodies that include most strains • Optimize the beads and reagents • Test at other locations • Test whether it is a stand alone method or can be used in existing models, integrate in predictive models • Epidemiological study - SCCWRP Transfer technology to local agencies

42. SOLUTIONS? PREDICTIVE MODELS RAINFALL BASED ALERTS • Stamford, Ct (20 years) • Door County and Milwaukee, Wi • Southern Ca (10 years) • Delaware (12 sites) • Myrtle Beach, SC • Boston Harbor • Ozaukee County, Wis • (may use in 2008)

43. SOLUTIONS? • MULTI-VARIABLE STATISTICAL MODELS • Linear relations between variables and E. coli • Use statistical techniques such as multiple linear regression • Beach specific models • Does not require identification of the source r=0.56 P<0.0001

44. SOLUTIONS? • STATISTICAL MODELS • OPERATIONAL MODELS • Project SAFE, IN (4 beaches, 3 yrs) • SwimCast, Lake County, IL (3 beaches, 1−3 yrs) • Chicago, (2 beaches, begin in 2008?) • Nowcast, Ohio, (1 beach, 2 years)

45. NOWCASTING AT OHIO BEACHES • Rainfall • Turbidity • Wave height • Lake level • Water temp • Wind direction • Day of the year

46. NOWCASTING AT OHIO BEACHES Huntington and Edgewater • Wave height • Turbidity • 48 hr weighted rainfall (Airport) • Antecedent dry days • Radar rainfall • Day of the year • Lake level Huntington, Bay Village Output from the model is the probability that E. coli will be >235 CFU/100 mL Threshold probability ranges from 27 to 32%

47. Edgewater wave height buoy

48. Ohionowcast.info

49. NOWCAST results in 2007 Edgewater, Cleveland, Ohio

50. Next steps for NOWCAST • Villa Angela and Lakeshore, Ohio • Standard was exceeded on the majority of days tested • Correct responses—Model 61-63%, Current method 73-75% • Consider using QPCR or IMS/ATP • Huntington and Edgewater • Improve performance of the model • Enable real-time measurements